Gas separator for pumps



A. ARUTUNOFF y GAS SEP'ARATOR FOR PUMPS Filed Aug. '7, 1933 2Sheets-Sheet l @Mew/Ms Jan. 4, 1938. A. ARUTUNOFF GAS SEPARATOR FORPUMPS 2 sheets-Spat Filed Aug. 7, 1935 @Hm/MM35 Patented Jan. 4, 1938IUNITED STATES PATENT. oFFic-E GAS sEPAnA'ron Fon PUMPS Armas Arutunoir,naruesviue; oki.y Application August, 7, 193s, serial No. 683,967 zclaims.' (cuss-2.7)

This invention relates to `improvements in a gas separator for use inoil well pumps.

The pumping `of oil wells is handicapped by gas even if the pump isinstalled close to the bottom of the well and the liquid stands vhighabove the pump, and the well produces no gas when standing idle, thewell starts producing gas as soon as pumping begins. As pumping lowersthe column of fluid standing in thewell, it lowers the pressure existingat the bottom of the well. Under decreased pressure, gas which issuspended in the liquid liberates itself in the form of free gas. Thecapacity of the pump is impaired to the extent of the volume of gasentering the pump. If at certain decreased pressures the volume of gasliberated at'the pump intake is equal to one-half of the total volume ofsaid pump intake then the capacity of the pump is only one-half of thenormal capacity. Such a condition is commonly referred to as the pumpworking at volumetric ef'- ciency; i. e., 50% of its full capacity. As amatter of fact, the pump works at capacity all ofthe time andtheexpression above is to be understood as a condition at which the pumphandles 50% liquids and 50% gases by volume.

In order to produce fluid out of the well, it is imperative that thepressure inside of the well be less than the pressure iny the stratumsupplying the fluid.` The `maximum rate of production will `be caused ifthe pressure in the well is reduced practically to nothing; i. e., thecolumn of fluid lowered almost to the bottom of the well. However,liberation of gases interferes with the lowering of the column `below acertain point. Even if the pump is of sufficient capacity to handle allof the fluid which the `well will produce at its highest rate ofproduction, `in the,wells with liquids `containing large amountsl ofdissolved gasrsuch a pump succeeds in loweringlthe column only to anegligible `degree` The majority of wellswithhigh standing fluid rleveland large amounts of gas. dissolved in liquid,r at present, are pumpedatthe rate which is only a smalL fraction of what thawells wouldiproduce if `not forreasons of gasinterference. To get the full`beneftyof -pumping,equipment of any kind or type, it is necessary thatonly liquids find their way toward the pump. The liquid has to bedirected toward the intake of the pump While gas has to he directed tothe opening of `the well, gas, by virtue of its low speciic gravity,rises and does not need any lifting equipment for delivery to thesurface. Various devices have ,been designed to prevent gas fromreaching the intake of the pump but owing .to limitations of availablespace and rather to lack of knowledge in regard to physical phenomena tobe handled, there has been very little success in this development. 5Separation of gas from liquid is accomplished on the principle ofgravity. Liquidismoved downward towards the extension of the pumpintake, while gas or gas bubbles donot follow the downward motion of theliquid. In order that such sep- 10 aration be effective, it is necessarythat the downward motion of the liquid be of a very small velocity. Inmaking a small `velocity possible for a given capacity of the pump, itis necessary to use a very large area. of passage or passages. 15According to my design, the preferable forms of which are shown on thedrawings, the area of downward directing uid passages may be of anymagnitude irrespective of the diameter of the well. 'Ihis purpose isaccomplished by staging vertically a number of separating devices insuch a way that all passages lead to the pump intake.`

An object of this invention is to provide an efcient means forseparating gas from liquids to be Dumped. 25 Another object is toprovide a self-contained separating device of small diameter and largecapacity.

Still another object is to provide in a device of the type mentionedabove, means for separat- 30 ing and segregating foreign mattersendangering the pump.

With the-above and other objects in viewwhich Vwill appear as thedescription proceeds, my invention consists of the novel features`herein il- 35 lustrated in the accompanying drawings and moreparticularly pointed out in the appended` claims. Y .l ,i

,Y `Referring to the drawings in which numerals of like characterdesignatesimilar parts through- -10 out the several views, Figurel is alongitudinal. sectionalview of one-form of my multi-stage gasseparator;l-I i q q y i `Figure 2. is another-sectional view of the`same separator Vat right angle to sectionl indicated 2 2 45 (Figi).l w.

Figure 3 is'another A"form of my multi-stage gasjseparatorshowing ascreen attached to the` extension of pump intake beside the settlingreservoir for sand below. 50 Figure 4 shows the embodiment of gasseparator of my invention with the necessary modification in design whensaid separator is made of sheet metal or of tubular goods.

Figure 5 shows a modication when the device 55 l nected to the pumpintake;

is made of separate parts assembled on the delivery tube.

Figure 6` shows a simplified form of rmy multistage gas separator whenno central intake tube is used.

In the drawings I indicates the upper part of l the gas separator bymeans of which it is con- \2 is the separating unit of the gasseparator. V3 is the'lower part of the gas separator to which a Asandtrap may be attached if it does not form'the integral part of it.d/designates ribs which connect the individual members 2.

5 designates a vgas screen which is .normally attached at the' end ofthe separator delivery?) tube 6.

.with part I to the pump intake and is lowered into the well and underthe fluid. .When the pump starts, the fluid enters passages formed bypartitions 2 and is compelled to move downward and towards the intake ofthe pump'. The gas separation takes place immediately where the uid owisreyersed; i. e., directed downward, while separation of foreign mattersuch as sand and the like takes place where direction' of uidis reversedagain. The design employed .allows any'desir'ed area of passages thusmaking it-ppssible to keep the fluid downward velocity to such smallmagnitude lthat an eiiicient gas separation occurs at every opening onthe cylindrical surface `of the gas separator.

To understand the principle of this invention it must be realized thatin order to have an eiiiclent gas separation, the velocity of flow hasto be suiciently low so that there is a viscous and not a turbulent -ow.Under the conditions of a viscous ow the resistance is in proportion tothe length of the path traveled,. and it is important to note that thelength of said travel does not consist solely of the path inside of theseparator, but includes the upward travel in the annularspace'betweenthe separator-and the well casing, thi reverse travel intheseparator proper and the upwad travel in the separator.

In Figs. 1 and 6, I have shown with arrowheads and lines, the iiow ofthe fluid in these two forms f 'my invention. Naturally all iluid comesfrom below the separator and in the case kof the structure shown in Fig.6, each particle of iluid travels the same distance and undergoes thesame two changes in direction of travel. That is, starting with itsinitial upward travel between the well casing and the separator, it isiirs't caused to reverse its ow downwardly between the separatingelements 2 and then again reverses its direction of iiow and passesupwardly through the pump intake. Granting that the crosssec- 'tion ofthe cylindrical passagejA is equal to the v'cross section of the annularpassage B between the casing and the outside diameter of the gasseparator, the velocity of the ow will be equal in both passages A andB,and as the length of travel is also equal, each inclined passage 4 lwill receive its proportionate share of the total iow irrespective'ofthe number of passages provided. This is clearly shown by the arrows inthe drawings. y

f In order. to counteract the eectof increased gas content of the liquidaround the separator,

it is desirable to retard the downward velocity ,of 4the flow as the gascontent increases. This is accomplished as shown in Fig. 1A by providingthe delivery tube 6 which extends downwardly from the pump and isarranged co-axial .of the separating elements. Although this tube ispreferably provided with perforations l2 spaced apart a predetermineddistance, I do not intend to confine myself to such perforations, asthey may,`

if desired, be eliminated.

The delivery tube is an incentive to a larger flow or higher velocitythrough the lower passages, and a smaller iiow or lower velocity throughthe upper passages, which is required to accommodate gas loaded liquidall along the separator in an eicient manner as it is evident that byproper dimensioning of the length of the delivery tube 6, the annularspace around the delivery tube, the perforations inthe delivery tube andthe annular space 'around the separator, any desired characteristic ofthe gas separator may be obtained. l

From the foregoing, itis believed' that my invention may be clearlyunderstood, it being borne in `mind that numerous changes in details -ofdesign may be madevwithout departing from the spirit of my invention asset forth in the following claims.

Il claim:

1. A multistage gas separator adapted for connection to the intake endof a well pump, includingan outer member forming a series of superposedco-axial annular deflectors, the walls of lwhich project downwardly andinwardly and terminate in open bottoms, rib means connecting saiddeflectors in vertically spaced relation so that the corresponding wallsof adjacent deflectors form a series of unobstructed parallel downwardlyand inwardly directed intake passageways of substantially uniform area'throughout and open at their inner and outer extremities, means closingthe bottom of the lowermost deector, and an inner member comprising adeliverytube -open' at its lower end'and adapted to be connected at itsupper end to theintake of a pump,-the lowermost of 'said deflectorsdefining an unobstructed inlet chamber, said tube extending downwardlytlrough the central openings of said deectors in spaced relation theretoand terminating at the top of said chamber.

2. A multistage gas separator as claimed in claim 1 wherein saiddelivery tube is provided with a series of vertically spaced intakeopenings, in line with certain offsai'd passageways.

ARMAIS ARUTUNOFF.

